BOSTON — Cost-cutting on the over-budget Green Line Extension project should be “on the side of brutal” and stakeholders “need to wrap their arms around that reality,” the chairman of the MBTA’s control board said Wednesday.

“The cutbacks of scope really need to be on the side of brutal,” Joe Aiello, the chairman of the Fiscal and Management Control Board said Wednesday, anticipating that third parties – such as cities and developers along the route – would have limited ability to contribute to the project. “This has to be a bare-minimum system in order to get to a point financially where we’re making a minimum ask to third parties because the state’s capped.”

Last summer, MBTA officials warned that on its current pace the cost of the project could rise to $3 billion from the roughly $2 billion price tag assigned the project a year before.

Jack Wright, the interim project manager for bringing trolley service into Somerville and Medford, agreed with Aiello’s characterization while leaving open the question of the project’s current bottom-line cost.

“I think they’re going to need to be on the side of brutal if we’re going to get it back. If it is a $3 billion project right now as has been implied by at least some, and there’s certainly a lot of escalation in this project,” Wright told reporters. “If that’s the case then something very dramatic’s going to have to be done to get it back.”

Wright noted that the seven stations envisioned for the project exceed much of the rest of the Green Line, where at some places little more than a strip of asphalt and street furniture serve as a trolley stop.

“I don’t know that that extreme would be applicable here, but it’s a long way from that,” Wright said. He said, “I wouldn’t call anything superfluous or fat at this point. It is a very nice addition to the Green Line . . . It is more than what the rest of the Green Line looks like.”

Wright said it would be important to differentiate between the “essential” and “nice” aspects of the 4.7-mile plan to add trolley alongside existing commuter rail tracks.

Fundamental changes to the scope of the project could violate the grant agreement with the Federal Transit Administration, which plans to contribute $1 billion, Transportation Secretary Stephanie Pollack said last year.

An MBTA consultant has raised the idea of converting a spur to Union Square into something less than a full trolley station – substituting a commuter rail stop or using shuttle service potentially – though Somerville Mayor Joe Curtatone said that might violate the FTA agreement.

Wright said he would need “more time” before making a recommendation on whether Union Square should be something less than a trolley stop.

Members of the control board expressed some concern about typos within a schedule Wright presented to them.

“Having a start date four days before an end date for a [memorandum of understanding] probably isn’t feasible,” said control board member Lisa Calise.

Wright noted to the board that “obviously misinformation is not what we need at this point,” and told reporters he did not think the mix-ups should be cause for concern.

“I don’t think the typos have anything to do with anything material on the project,” Wright said. He said, “The typos come from my focusing on the completion dates and not looking at the start dates.”

The MBTA provided a corrected version of Wright’s presentation during a joint meeting of the MBTA Fiscal and Management Control Board and the Massachusetts Department of Transportation Board of Directors.

The document showed potential negotiated agreements with Cambridge and Somerville beginning April 1 and ending May 31.